Image Analysis Methods In studies of body composition, MRI and CT scans are often obtained in different locations in the body for muscle and adipose tissue assessment. Data acquisition is only one part of the process. Programs must be created that would allow for the easy analysis of data contained in the scans. This process involves uploading of the scans into the analysis program (made possible by enabling easy access of critical header data in the analysis program), easy-to-follow instructions on processing the data, troubleshooting steps, and downloading of both intermediate data for future analysis and final data results. While there are many specially-constructed programs for analysis of scan data, we are working to develop a freeware analysis tool to measure muscle and adipose tissue from MRI and CT scans. Voxel-Based Morphometry and Finite Element Modeling Risk of hip fracture is the result of a complex interaction between factors governing bone biology and factors predisposing to falls. Efforts are currently directed to improvement of techniques for detection of risk for both of these factors. For bone, the value of improving estimate of risk by inclusion of measures of bone quality as well as bone density has been endorsed, but it is as yet unclear what measure of bone quality will prove to be more specific for risk than hip bone mineral density as assessed by dual energy x-ray absorptiometry (DXA). It has been suggested that quantitative computerized tomography (QCT) may have some advantages over DXA because it allows characterization of the trabecular and cortical bone separately and thus may provide a better estimate of bone strength and the relative compensatory enlargement in cortical bone for the decrease in trabecular bone. Quantitative computerized tomography also offers the opportunity for calculation of finite element models, another estimation of bone strength based on accurate depiction of bone geometry and the orientation of loading forces based on that geometry. Using QCT images obtained in the examinations of the Health ABC and AGES-Reykjavik studies, we use morphometric methods to infer biomechanical physiology of the bone. This project will test a novel radiographic analytic technique, voxel-based morphometry (VBM) of the femur.